1. Field of the Invention
The invention is a process by which a package of fiber (yarn) may be unwound in a manner such that the revolution of the unwinding process may be controlled relative to linear payout speed of the package. This invention may be applied to a variety of processes, but has particular interest in a textile beaming operations where multiple packages are unwound and then re-spooled together on another holding vessel, frequently a flanged beam. The preferred embodiment is a textile warping or beaming operation where a low-twist yarn (less than 2.5 turns per inch) is being processed. Yarns processed can be any textile continuous filament, monofilament, or staple yarn, such as fiberglass, nylon, polyester, polyethylene, denim, cotton, or aramid yarns.
2. Description of the Related Art
The conventional warping and beaming processes in textile operations usually consists of loading a number of packages onto a creel, or package holder, and simultaneously pulling the yarn off the packages to be spooled together onto a beam. This method traditionally utilizes a static package holder such that the packages are loaded onto a pin, clamp, bucket, or platform. The yarn is then pulled off of the packages such that the yarn is either rotating around the outside of the package as it is paid out (in the case of outside draw packages) or rotates around the inner circumference of the package (in the case of inside draw packages).
In this conventional process, each revolution of the yarn as it is paid out imparts an additional revolution of the yarn bundle or twist. Expressed differently, each payout revolution imparts an additional turn of the yarn, either increasing or decreasing the number of turns per inch, depending on the direction of the yarn""s inherent twist and the direction of the payout revolution. Interestingly, because the length of one payout revolution changes with the decreasing package size as the circumference changes, the amount of twist imparted or removed during this process changes through the run of the package.
With a processed yarn that has been through a twisting operation prior to beaming, there exists a high number of twists per inch in the yarn before it is paid out in warping or beaming, and this twist is applied in a manner such that the yarn is secured in this twist pattern. Therefore, a single additional twist or untwist in the yarn every linear length equivalent of the circumference of the package is negligible. However, in low- or zero-twist yarns; this impact of the payout revolutions can be significant. The payout twist has an additional problem of significance in this operation. Because the payout twist is low in frequency, the impact of the additional twisting is a function of a cumulative build of twist tension in the process. The twist will begin to back-up behind a contact point in the process where the yarn is not permitted to easily rotate. At this point, the payout twist (one twist for each payout revolution) begins to cumulatively add together behind this contact point until there is enough tension from the twist to overcome the static resistance of the contact point. In this manner, a large cumulative build of twist is released into the line at one time, and causes difficulties in the process with yarns that have not been previously twisted. The impact in the processing of the yarn consists primarily of individual yarns having a tendency to curl and coil around each other at the point that the payout twist propagates through the line.
With conventional methods, the impact is often disguised for two reasons: First, the yarn generally has already been twisted on a twist frame prior to the warping operation. This previous twisting step has the tendency to greatly reduce the cabling or coiling encountered during warping. Second, after warping, an additional process step called slashing applies a polyvinyl alcohol or starch-based coating on top of the yarn bundles. This aids in providing a layer of softer material that can shear during weaving operations, allowing the yarn ends that are crossed an opportunity to abrade the coating as it un-coils, rather than abrading the yarn itself. Although the invention covered in this application will make improvements in the standard, conventional methods, the current methods allow product to be produced. The nature of the impact has remained out of notice until the impact on very-low twist yarns was evidenced.
Most conventional operations utilize a twisted yarn supply, and thus this inherent problem for very low twist yarns has remained hidden, and has historically not impacted the warping or beaming operation. This is also the reason the problem and solution were not readily apparent even to those highly skilled in the art, and which makes the solution in this invention application novel. Indeed, several months of operations were pursued trying to simply discover the cause of the defects, and additional time spent on devising the solution.
It is therefore the design of this process invention to provide a method to improve the warping and beaming processes of textile operations by means of an alternate payout method of the yarn fibers. Rather than fixing the package holder and allowing the yarn to revolve around the circumference of the package, thereby imparting an additional positive or negative twisting action, the packages will be rotated at the line speed of the operation. This will allow the yarn to be paid out in a manner such that the yarn bundle does not rotate and xe2x80x9cflip overxe2x80x9d itself and imparting a twist for each revolution.
The preferred embodiment of the yarn is a warping operation of glass fiber packages that have been produced such that the yarn is paid out from the inside of the package. Alternative fibers and payout methods will equally benefit from this process invention, as the basic physics of the action remain the same regardless of substrate of packaging means. As long as the package has previously been static in mounting, the process invention will improve the consistency and runability of the operation.
The process invention comprises: a method of mounting a package so that it may be driven and rotated according to the operational requirements; a drive system designed to perform the work of rotating the packages; a controller to adjust the rotational surface speed of the packages to the line speed of the operation; and a feedback system to correct differences between the rotation and line speeds.
Packages are mounted in a truck so that the yarn packages may be paid out from the inside of each package. The packages have a cylindrical-like shape, and are placed inside a series of fingers that grasp the outside of the package, so that the hollow end of the cylinder faces the draw direction of the warping process. These fingers are mounted on a back plate of rigid material that is attached to a drive shaft. The drive shaft is free to turn and is mounted with bearings to a rack or truck system for orienting the packages to the warper creel. On the rear of the drive shaft is a pulley or gear that is attached to the drive belt or chain. On a single truck of packages, the entire system of packages is ganged together onto a single main drive belt or gear, which is attached to the motor. A motor drive signals the motor to rotate at the appropriate speed to match the warper line speed. The motor drive is in communication with the main drive of the warper system for signaling start, stop, and speed changes. Further, a feedback system to gauge the accuracy of the drive signal can be installed, linked to the controller and line speed.
We provide a process for making a warp beam of untwisted fiberglass strands comprising: providing a fiberglass forming package with a single fiberglass strand wound on the package and having a longitudinal axis; supporting the package in a manner that permits rotation of the package about the longitudinal axis; rotating the package; pulling the single strand from the package while simultaneously rotating the package; and wrapping the single strand which is pulled from the package onto a beam which can be used to form a warp beam. We further provide using a plurality of fiberglass forming packages and wrapping the respective plurality of strands onto the beam.
We maintain a rotational surface speed of the package equal to a linear speed of pulling the single strand. The rotation of the forming package is done in a direction of rotation opposite to a direction of rotation in producing the forming package such that the fiberglass strand is pulled off the package with a net zero amount of twist.
We weave the strands from the beam with other strands of fiber glass having zero twist on a loom to form fiber glass cloth.
A warp beam made from untwisted fiberglass strands is also especially well suited for the manufacture of a tape. A tape which is reinforced with fiberglass strands, commonly known as filament tape or strapping tape, is available which uses alternating strands of right-hand and left-hand twist to avoid the tendency for the tape to curl and twist. A similar product made from untwisted fiberglass strands using the present invention would avoid the need and expense of alternating strands of right-hand and left-hand twist.